expense是花费或者开支的意思，fee则是费，而due则是到期的意思，区别可以从以下例子看出：
We have to control our expense, as the insurance and registration fee for car will be due by the end of the month. 我们必须控制我们的开支，因为汽车的保险和登记费将在月底到期。
水利万物而不争,
而万物莫能与之争。
